Can I be allergic to the sun?
The answer is yes. All people, no matter what their skin color is, will react to sun in some way or form. For people who have fair skin, the result is pink/ redness, and sometimes a sun burn. For darkly pigmented individuals, the redness may not be appreciated, but the effects of sun can still be seen much after the exposure– in the form of post inflammatory hyperpigmenation. Yet, in few individuals, the reaction to sun is quite striking and exaggerated. In this case, a sun sensitivity may be suspected.
What types of skin diseases result in abnormal reaction to sun?
There are quite a few. The most well understood disease that results in sun sensitivity is Lupus. It is important to understand that there are many types of Lupus, and some of them only affect the skin, whereas other types can have more wide-spread involvement. A skin biopsy and certain blood tests are often needed to make this diagnosis.
More commonly, the cause of polymorphic light eruption. A type of sensitivity that erupts often hours to days after initial sun exposure and is worse during the spring, and seems to get better by the end of the summer. In most cases a diagnosis can be made without a skin biopsy but sometimes may be desirable to firmly establish the diagnosis.
Solar urticaria, Hydroa, phytophoto dermatitis and other rarer diagnoses also exist. A thorough evaluation of sun exposure habits, onset of eruption in relation to exposure patterns are often needed to come up with an acurate diagnosis and treatment plan.